Pursuant to IPC, the invention refers to processing of plastics, namely to formation or interconnecting and subsequent treatment of formed products, and quite exactly to connecting each product by means of a thermally shrinkable film. Moreover, the invention may also refer to multi-layered packaging containing artificial resins, in particular polyester.
The purpose of the invention is to create a thermally shrinkable wrapper, which should be suitable for use in sterilization process and will at least in transversal direction be sufficiently strong for the purpose of binding of object wrapped therewith, and which should be also easily removable after the shrinking thereof.
The invention refers to a packaging in the form of a sleeve, which is made of a thermally shrinkable material, which is shrank by means of thermal energy during a process of sterilization, so that the sterilization package is firmly bound, although the sterilization media is still allowed to penetrate towards the interior of said package.
In the process of sterilization of heavier units of surgical instruments, which are usually named sets or nets, a double-layered wrapping into sheets of sterilization paper or any other suitable sterilization material is used. Special adhesive bands, which are suitable for use in conditions during said process of sterilization, are used in order to prevent unwinding of such bundles.
Classical wrapping as commonly used packing into said flexible sterilization packaging excels essential benefits when compared with other methods of sterilization packing due to relatively large dimensions, which by unwinding enable covering of working surfaces and herewith also protection of a sterile working area. The main deficiency of such classical wrapping results in a relatively complicated process of manual wrapping, which essentially depends in a human factor. Another deficiency of such classical wrapping furthermore results from the use of adhesive bands, which sometimes stick out due to conditions in the sterilization process, so that the sterilization bundles become unwound, and are moreover also difficulty removed in situ, which may jeopardize aseptic conditions. Parameters of packing each sterile items, which are prescribed by IS0-11607 standard, however cannot be assured by using such classic wrapping.
The proposed wrapper is produced in the form of a sleeve with appropriate dimensions, which is then cut by user to each desired length, which is adjusted to each sterilization packaging, and by which a classically wrapped packaging is dressed prior to inserting it into each sterilization appliance for the purpose of sterilization. During sterilization at increased temperature, the wrapper is shrank, by which the packaging is compressed, by which then the windings of said classic sterilization wrapper are fixed. Thanks to sealing and shrinking, the human factor is eliminated, and moreover, there is no need to use said risky adhesive bands, by which the requirements as prescribed in said IS0-11607 can easily be fulfilled.
The wrapper consists of a material, which is resistant during all stages of each process of sterilization. Penetration of each sterilization media is achieved by means of perforations available on said thermally shrinkable material. During the process of sterilization, the material is initially shrank, by which said perforations open and enable penetration of said sterilization media during the process of sterilization.
Aseptic presentation in situ is easily achieved by means of one or more longitudinal bands, which are easily removable by simply tearing-off, upon which a sterile packaging is released and is suitable for further unwinding and presentation.
A wrapper in accordance with a further aspect of the invention can be manufactured in combination with a barrier layer, wherein such barrier material is intended to prevent from intrusion of microorganisms. A thermally shrinkable material then establishes a mechanical protection of said barrier layer, wherein said thermally shrinkable material serves as a stand-alone system of sterilization packing. Such combination is achieved either by laminating, welding or any other combining of materials in such manner, that a perfect barrier against intrusion of microorganisms is achieved. An important innovation in manufacturing of such packaging relates to longitudinal ultrasonic welding of two thermally shrinkable layers with an intermediate band, which consists of a thermally stable material and is inserted there-between in order to reinforce the weld, which is however easily removable by simply tearing-off: by which the packaging is then open. The lateral weld is actually a weld, by which three layers are interconnected, namely a top thermally shrinkable layer, a thermally stable intermediate layer, as well as a bottom thermally shrinkable layer. Each weld in such combination is extremely strong in the transversal direction and enables each desired compression and fixation of the package, but is also pretty weak in view of cutting effect in the longitudinal direction, which is used for opening the package, since by simply tensioning one terminal portion of the band the longitudinal weld is tear-on which enables perfectly aseptic opening of the package.
The invention provides a sterilization wrapper, which consists of a thermally shrinkable material and is characterized by shrinking by means of thermal energy during the process of sterilization for the purposes of fixation of a primary sterilization wrapper.
The invention further provides a packaging in accordance with previously mentioned features, which is manufactured in combination with a barrier material in such manner that said barrier materials prevents from intrusion of microorganisms towards the interior of each sterile package, for the purpose that such packaging represents a stand-alone system of packing in each process of sterilization.
The invention further provides ultrasonic welding by using an intermediate band consisting of a thermally stable material and being inselied between two layers of a thermally shrinkable material, which enables realization of welds, which are sufficiently strong in the transversal direction, and on the other hand easily opening of each package by means of tearing-off and disruption of the welds in the longitudinal direction thereof. Provided is also opening of a thermally shrinkable package by means of tearing-off the weld, which is reinforced by a thermally stable material extending in the longitudinal direction of the weld, by means of cutting effect.
A thermally shrinkable wrapper is disclosed in WO 2005/011978 A1, JP 11227805 and U.S. Pat. No. 3,429,433.
In accordance with the invention, the previously mentioned problem is solved by means of a thermally shrinkable wrapper, which is in particular suitable for use in sterilization process and which comprises:                a first layer consisting of thermally shrinkable film in the form of endless band of pre-determined width and with at least approximately linear longitudinal edges defining a longitudinal direction of the wrapper        a second layer consisting of thermally shrinkable film in the form of endless band of pre-determined width and with two at least approximately linear longitudinal edges, which is placed over said first layer, so that both pairs of longitudinal edges are at least approximately aligned with each other;        a pair of bearing bands consisting of thermally non-shrinkable material, wherein each of them is integrated and welded between said first layer and said second layer in the area of their aligned longitudinal edges,        
wherein each of said thermally shrinkable layers is furnished with a plurality of perforations, which are arranged in the form of an uniform raster along the lines, which extend equidistantly with respect to each other in the transversal direction of the wrapper and are also equidistantly arranged in the longitudinal direction of the wrapper, and wherein each connecting area between each bearing band and said first and second layer is formed of groups of welds, which are equidistantly spaced apart from each other in the longitudinal direction of the wrapper and are present on both bearing bands as well as on both layers adjacent to said longitudinal edges thereof, so that each group of welds comprises at least two welds, which each per se extend in the longitudinal direction of the wrapper and are spaced apart from each other in the transversal direction of said wrapper.
In a preferred embodiment of the invention, each of said perforations is conceived in the form of letter S and comprises a linear central section, which extend in the transversal direction of the wrapper, and substantially semi-circular terminal sections, which are in the longitudinal direction of the wrapper arranged on different sides of said central section, wherein the orientation of said terminal regions remains equal in all perforations, which are repeated both in longitudinal direction and transversal direction of the wrapper.
It is in particular preferred, when each group of welds comprises at least three linear welds, which are aligned and equidistantly spaced apart from each other in the transversal direction and
Each weld is selected from the group, which includes laser welds and ultrasonic welds.
Each of said thermally shrinkable layers consists of material, which is independently selected from the group, which includes polyethylene (PE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP) and polyolefin. When the wrapper is used in process of sterilization, the invention is further characterized in that each of said thermally shrinkable layers consists of material, which is shrinkable at temperature below the temperature, which is required for sterilization of each substance or each object wrapped with said wrapper.
Each of said bearing bands consists of a thermally non-shrinkable non-woven material, in which polyester is dominant.
The invention further provides use of the wrapper according to previously stated features a process of sterilization of surgical instruments.
The use of such wrapper is moreover foreseen in a process of sterilization of surgical instruments, which are placed on a plate and wrapped with a woven or non-woven flexible material, which is suitable for application in the process of sterilization of surgical instruments.